The atmosphere surrounding a surface of the Earth has a great influence on human life. Among the observation apparatuses used for understanding the structure and change of the atmosphere, a radiosonde is the observation apparatus mounted with temperature, humidity, and GPS sensors which is suspended from a balloon and sent into the atmosphere, and which then understands the upper air condition by receiving observation data transmitted from the observation apparatus at a regular interval of time.
The radiosonde measures directly the temperature, pressure, and humidity, etc., by flying in the atmosphere, and the wind is calculated by understanding flying distance of the balloon for a period of time. As a method of understanding a location of the radiosonde, Long Range Navigation (Loran) and Global Positioning System (GPS) have been widely used.
For example, a lower atmosphere ascending/descending-type experimental observation apparatus, disclosed in Korean Patent No. 10-1045827, allows accurate observation results to be known when temperature, humidity, etc. are observed through various sensors and output to the ground.
A conventional radiosonde usually uses only one temperature sensor. Such a radiosonde is continuously subjected to energy irradiated from the sun while flying as high as the stratosphere. In this process, undesirable temperature rises due to the irradiance may occur, but a method of correcting risen temperature due to the irradiance was not developed in the related art, so the temperature cannot be measured accurately.
A method of using a pyrheliometer may be considered. That is, a method of measuring solar irradiance of particular area and particular time using the pyrheliometer, and then using it as a correction value may be applied. However, the irradiance is to be changed according to area, time, and weather condition; therefore this method is considered as a temporary method. In addition, the pyrheliometer is a relatively expensive instrument; therefore using the pyrheliometer is economically infeasible in an aspect of cost.
Accordingly, development of an accurate method of correcting rising temperature in the radiosonde according to the irradiance is required.